cleve_thompson

cleve_thompson

Well Known Member
I have a Garmin 430W, GRT Hor1, and Trutrak with GPSS and GPSVS and switch on the panel switching the source for Trutrak from the EFIS to the Garmin 430W.
Problem #1 I can't get the EFIS to show vertical guidance either on the PFD or the HSI page from the 430W when the 430W is in GPS mode and has a LPV approach loaded. I have the new software update for the GRT which now has GPSV on the menu. Still no joy! Why?

Problem #2 When I have loaded either a GPS or ILS approach in my 430W I can get GPSS commands to my TruTrak if I have the source switched to the 430W but not if I have the EFIS selected. BTW, it is really cool when I have the switch to the 430W to see the auto pilot anticipate the turns and follow directions for procedure turns, holding patterns (even knowing how to enter the hold).

Problem #3 If I have the TruTrak following the 430W as its source with GPSS, I can't set the TruTrak to GPSVS to couple with the glide slope on an ILS approach.

Problem #4 If I am using the GRT EFIS to send GPSVS commands to the TruTRak A/P on an ILS approach, when it captures the G/S it porpoises up and down and I don't know how to set sensitivity on the EFIS to stop this!
 
You didn't mention which TruTrak model you have and you should note that only the Sorcerer or AP-100 has the capability to track and an "actual" ILS. Theoretically you would think they should with the ARINC interface and vertical steering modes but GPS vertical steering is different than VHF/NAV vertical steering. So unless you have a Sorcerer or AP-100 which has VHF/Nav modes, it will NOT track the glideslope of an ILS--or even a VOR. That's the answer for #3.

As for question 1, 2 & 4, these are best put to GRT, since clearly the GRT is not sending the right (or any) information to the TruTrak.
 
This may help, maybe

Although my experience is with a '496, not a 430, I found that I had to make sure that the baud rate was 4800 going from the GPS to the Horizon EFIS and from the Horizon EFIS to the TT A/P. Yes, 9600 is available, but it did not work well on the Horizon EFIS. YMMV.
 
hevansrv7a said:
Although my experience is with a '496, not a 430, I found that I had to make sure that the baud rate was 4800 going from the GPS to the Horizon EFIS and from the Horizon EFIS to the TT A/P. Yes, 9600 is available, but it did not work well on the Horizon EFIS. YMMV.
Click to expand...
Good suggestion but not really applicable here. For GPSS and VHF/Nav to GRT, the 430 use the ARINC 429 data bus.
 
I have the Garmin, GRT and Trutrak setup and can answer some of the questions. I assume that you have the Socerer or RV-10 autopilot since the Digiflight IIVSGV does not have any ability to track a localizer / glideslope (AFAIK anyway).

1) I can't get the EFIS to show vertical guidance either on the PFD or the HSI page from the 430W when the 430W is in GPS mode and has a LPV approach loaded. I have the new software update for the GRT which now has GPSV on the menu. Still no joy! Why?

Likely the problem here is in the setup of the GRT. Go to the setup menu and check under PFD (I think, though it may be under general setup). About 2/3s of the way down the list there are options related to showing the GPS data.

2) When I have loaded either a GPS or ILS approach in my 430W I can get GPSS commands to my TruTrak if I have the source switched to the 430W but not if I have the EFIS selected

Can't help on this one.

3) If I have the TruTrak following the 430W as its source with GPSS, I can't set the TruTrak to GPSVS to couple with the glide slope on an ILS approach.

You use the NAV button to track the ILS localizer not the GPSV button. Roughly use the GPSS to get yourself to the inital approach fix (and do the procedure turn if you need/want to) then when you are almost on the inbound approach heading hit the NAV button, put in the approach course and the desired intercept angle and hit enter. The autopilot should intercept the localizer and turn inbound and announce that the glideslope is armed (this assumes you have the proper frequency tuned and that you are below the glideslope). When you get to the glideslope (from below) you will get another announcement "Glideslope coupled". It will then fly you right down to the runway. You have to monitor speed, trim and DA.

4) Problem #4 If I am using the GRT EFIS to send GPSVS commands to the TruTRak A/P on an ILS approach, when it captures the G/S it porpoises up and down and I don't know how to set sensitivity on the EFIS to stop this!

Can't help here, haven't tried it yet.

Finally and most important, have GRT on your speed dial. Carlos or Mark both have excellent knowledge of their product and are extremely helpful.
 
MSFT-1 said:
I have the Garmin, GRT and Trutrak setup and can answer some of the questions. I assume that you have the Socerer or RV-10 autopilot since the Digiflight IIVSGV does not have any ability to track a localizer / glideslope (AFAIK anyway).
Click to expand...
Bruce, Are you certain the RV-10 AP has VHF/Nav (localizer / glideslope) modes? My understanding is that only the Sorcerer and the AP-100 has VHF/Nav modes. The RV-10 AP is GPS only.
 
Bruce,
Thanks for the info. I think I will have to get back in the plane and try some of your suggestions. I will also give GRT people a call.
 
No, I am not sure

William:

I don't honestly know if the RV-10 does or does not have the ILS/LOC mode. I made the assumption that it does. I have the Socerer myself.
 
Avionics problems

Cleve,

Background: My RV-7A has a GNS 480, GRT H1 EFIS with ARINC module, and TT DFII GSGV autopilot with a switch to control whether the GNS or EFIS controls the autopilot. Controlled by the EFIS, the autopilot flies point-to-point with turn anticipation; complex paths (arcs, holding patterns, procedure turns, etc.); arrivals, approaches, and missed approaches with altitude constraints (e.g., climb to x,xxx' and then turn direct to the MAHWP, and level at y,yyy'); and coupled ILS, GPS (lateral + vertical), and synthetic approaches. I leave the switch in EFIS. It's only there to get GNS-direct control if the EFIS goes down.

First, do you have the three components wired according to the pfd diagram for the 430 with DF on GRT's site to include the ARINC module? Make certain that the ARINC connection speeds are set properly. The TT needs low speed and the EFIS, and probably the GNS 430, can transmit at either high or low. In my system, all ARINC connections are low. Ensure that the GNS 430 protocols are correct. My GNS 480 sends "GAMA 429 NO FP" to the EFIS and autopilot (switchable) and "VOR/ILS" to the EFIS. Make sure that the EFIS setup menu choices are correct. If in doubt, choose "yes" for entries that determine whether or not something shows.

P1 (no LPV GSI): Is the EFIS glide slope indicator (GSI) visible for an ILS? Did you simply load the LPV or did you fly it to the point where the glide slope indications were valid? I'd need to confirm airborne, but believe that the EFIS will not show the GSI until it's valid. For LPV or LNAV/VNAV approaches, that may not occur until the GPS has switched from terminal to approach mode.

P2 (With EFIS control, TT will not follow GNS 430 GPS or ILS steering): With the EFIS control, if you engage the TT and push the MODE button on the TT, do you see GPSS on the lower left of the TT display? If so, you should be able to get the EFIS to control heading with LAT A/P in HDG. True? Can you use the EFIS to command an altitude change (TT in GPSS + GPSV). If so, the EFIS-to-TT connections should be correct and the TT should be able to fly a coupled SAP. True?

P3 (GNS-direct ILS): TT hasn't included the feature in the DF series. Without the EFIS, the only vertical steering capability the DF offers is control of vertical speed with the knob on the autopilot control head.

P4 (ILS porpoises): Your statement of P2 indicates that the EFIS would not control an ILS or GPS and here we have porpoises at ILS GS capture. Regardless, the TT vertical activity level may be too high. Mine is 3 but if the porpoises only occur at capture, the level is probably not the cause. There is (or at least used to be) some gain settings at the end of the EFIS General Setup menus for the MFD with the ARINC module. The defaults are 1.00 and I set the one for altitude control to 0.5 so long ago that I cannot remember why. In the distant past, I have had some minor pitch transients in cruise immediately after exiting setup to refine the tank calibration table numbers. The transients would quickly dampen, have been few, and have never occurred on during a coupled approach; and I have flown them in pretty bumpy conditions with lots of wind (58kts at 1,500' last month).

John Nystrom
RV-7A, N7VD
 
My 7A has the same equipment (dual Horizon I, GNS430W and TrueTrak Digiflight VSGV) and all the functions work beautifully. When the auto pilot is driven by the EFIS it will fly coupled approaches chosen in the 430W and the needles and HSI are displayed on the GRT screens. It also flies the WAAS approaches including vertical profile. The key was setting the ARINC speed to low as the previous poster pointed out.

As far as porpoising when intercepting the glide slope is concerned I discovered that it was a trim issue. The trick is to trim for a chosen approach speed when in level flight (I use 120mph) and then maintaining that speeed as the glide slope intercept occures by manipulating the throttle. If you do that the intercept and final approach is very smooth. My vertical sensitivity on the EFIS is set to 1. I have found that this systrem will nail the localizer and glide slope with the cross hair on the HSI centered even in turbulence AS LONG as you maintain the approach speed you trimmed for.

Great Stuff!

Martin Sutter
building and flying RV's since 1988
 
John,

Thank you for the most detailed review! I have exactly the same equipment setup as you do except that I have the 430W instead of the 480. I just hope that I will get all the bugs worked out so that I can do all the things that you do. I think that that would be wonderful!!!

I don't know about how all the components are wired for I have a plug and play panel from Aerotronics but I suspect that they did it right for I have not found anything else that was not first class. I will go through all the EFIS setup again and do like you suggest. I will set every thing to yes that I have question about.

Now to the problems.
P1 No G/S on PFD. Yes the EFIS glide slope indicator is visible for a ILS approach. I have hand flown the LPV approach as I would a non-precision approach and still didn't get a glide slope. I do get a synthetic approach with HITS when the LPV approach is loaded into the 430. I think that I see a indicator that the GPSV approach is "armed" in the upper left corner of the screen, but I don't think:confused: I have ever seen it say that it has captured but I could be mistaken. I plan to call GRT tomorrow to see if they have any suggestions.

P2 Yes I see GPSS in the TT display and it will fly a flight plan but just won't fly the intercepts and holds etc. when I have the switch to the EFIS. I can also make turns with the EFIS in NAV mode. I just can't get it to follow the course reversals etc. I can switch the TT so that it is controlled by the 430 and when established on the loc, I can switch to the EFIS and it will do an altitude hold until the G/S is captured. I have not tried a coupled SAP approach.

P3 I understand now why I was having P3. I somehow had missed this important piece of information, but if I get the EFIS to working that should not be a real problem. Like you say, I can control the descent with the altitude bug on the autopilot and can still fly a better approach than I can by hand! Aren't modern avionics great....if you can figure them out.

P4 I have my TT vertical activity set to 6 and it doesn't porpoise in altitude hold but does not always hold altitude in rough air so I might have to set it lower. Maybe if I set my EFIS PFD level I could stop the porpoise on G/S. I think that there is a setting just for G/S and mine is set at 1 and I couldn't figure out which way I was supposed to change this setting to control porpoise. I will try 0.5. I didn't know you could go lower than 1. I will also check this out with GRT

Again, Thank you John!!! BTW, where in the world do you fly with 58 KNTs at 1,500. I surely don't want to exchange our relatively benign weather here in south Georgia for that. We do have some rough thunder storms during the summer though.
 
Martin,
You posted while I was composing an answer to John. You also some great suggestions that I will try tomorrow if the weather is OK. I will look in the setup and see if the ARINC speed is set to low . I will also make sure that I am trimmed correctly. I have noticed that in altitude hold, I get out of trim indications on the TT display but they don't seem to be there during the coupled G/S approach. I will just have to be more careful about my speed during the approach. I have been starting out at about a 120MPH and then slowing down to 100MPH as I near decision height so my trim requirements have been changing constantly.

Thanks to Van's Air Force forum and all the great members, I will probably be busy trying all these things out for the rest of my phase I flights. I now have 22 hours flown of the 40 required. I think people are getting tired of me flying so many approaches at our little airport, KAYS, Waycross.:)
 
More Suggestions

Cleve, I've inserted my comment in bold.

P1 No G/S on PFD. Yes the EFIS glide slope indicator is visible for a ILS approach. If you see the ILS GSI, you should see it for a GPS approach if the 430 CDI is in GPS not VLOC. I have hand flown the LPV approach as I would a non-precision approach and still didn't get a glide slope. Make sure that both Lat and Vert a/p functions are ON near the bottom of the General Setup menu. I do get a synthetic approach with HITS when the LPV approach is loaded into the 430. The HITS should not appear unless you selected SAP ARM or, if an ILS is armed, SAP DISP. I think that I see a indicator that the GPSV approach is "armed" in the upper left corner of the screen, but I don't think I have ever seen it say that it has captured but I could be mistaken. The top two text boxes in the upper left of the PFD show LAT A/P and CDI info. When you arm GPSV, the EFIS will add a third line reading GPSV ARMED with a yellow background. Unless the EFIS is getting GPS info, you cannot arm the GPSV. Same applies to an ILS. At glidepath capture, the third line will disappear and the second line will change to read GPS-V or GPS1-V in green depending on how many GPS units you have. At glide slope capture, the text in the upper RIGHT will change from GPSV ARM to GPSV CAPT, GPSV G/S CAPT or something to that effect. It's clear, I just can't reacll the words. The big clue is the nose drops.

P2 Yes I see GPSS in the TT display and it will fly a flight plan but just won't fly the intercepts and holds etc. when I have the switch to the EFIS. I can also make turns with the EFIS in NAV mode. I just can't get it to follow the course reversals etc. I can switch the TT so that it is controlled by the 430 and when established on the loc, I can switch to the EFIS and it will do an altitude hold until the G/S is captured. I have not tried a coupled SAP approach. You didn't mention if you could use the EFIS to change altitudes. If you can control altitude and heading with the EFIS, the EFIS is talking to the EFIS via ARINC. Sussessfully flying a SAP (no porpoises) would tell you if the gains are correct.

P4 I have my TT vertical activity set to 6 and it doesn't porpoise in altitude hold but does not always hold altitude in rough air so I might have to set it lower. The higher number makes the TT react faster (more jittery) so you should have tighter control. You can change the activity level while the TT is engaged; so, if you can stomach it, let it porpoise and run the level up and down. But, I suspect that if 6 works for all else, the level is not the problem. Maybe if I set my EFIS PFD level I could stop the porpoise on G/S. I think that there is a setting just for G/S and mine is set at 1 and I couldn't figure out which way I was supposed to change this setting to control porpoise. I will try 0.5. I didn't know you could go lower than 1. Before I'd fool with gains, I'd try a SAP.

Again, Thank you John!!! BTW, where in the world do you fly with 58 KNTs at 1,500. New Mexico, USA.

As mentioned in my last, check ARINC rates and protocols. Also, there is an ARINC Input Counter line near the top of the General Setup menu that should show activity (increasing numbers) if the ARINC is getting info.

Cheers,

John Nystrom
 
More ^2

Cleve,

I've inserted P2 from your initial post immediately below and make some comments after.

"Problem #2 When I have loaded either a GPS or ILS approach in my 430W I can get GPSS commands to my TruTrak if I have the source switched to the 430W but not if I have the EFIS selected. BTW, it is really cool when I have the switch to the 430W to see the auto pilot anticipate the turns and follow directions for procedure turns, holding patterns (even knowing how to enter the hold)."

Comments:

There are two possibilities. The first, is that that the you cannot get the TT in GPSS mode if the EFIS is driving. If so, the problem is likely EFIS setup or ARINC related, either wiring or configuration. Alternatively, if you mean that you cannot get the EFIS to command a holding pattern that's part of procedure loaded in the 430W, that's entirely different and I'll try to explain.

With ARINC, the EFIS actually commands the TT told hold specific bank angles and it does very well when maintaining straight paths or turning from one straight path to another; i.e., guiding you along a point-to-point flight plan. However, interpreting a Jepp IAP; where a single entry can be hold at a fix, right turns, with 1 minute legs; is more complex and beyond the EFIS's capabilities. But, it is not for the 430. It will monitor progress around the holding pattern while generating bank angle commands to maintain it. Even if the EFIS had the same code as the 430 to interpret a holding pattern entry and command the TT to fly it, it could not do it because the 430 does not pass the specifics of the holding pattern to the EFIS.

So, what do you do now? You must have the autopilot source switch in the 430 position to have the TT fly complex paths such as a holding pattern and forget about EFIS altitude control. To fly a coupled approach, the switch must be in the EFIS position. To have the TT fly the missed, you must switch LAT A/P from HDG to NAV and return the source switch to the 430 position. While the 430 controls track, you must manually control altitude.

There's better option coming where the 430's lateral steering commands will go to the EFIS via ARINC. There, the lateral commands will be joined by EFIS-generated vertical steering commands and the combination will go via ARINC to the TT. It means that the autopilot source switch can stay in EFIS all the time.

Consider this scenario: A GPS approach with a DA of 6,140' (yes, flat landers, if your field elevation is 5,834', 6,140' is an appropriate DA). The missed requires a straight ahead climb to 6,400' before turning to the MAHWP. You set the decision and missed altitudes in the EFIS, load the PROC in the GPS, and select GPSS+GPSV on the TT. You use EFIS altitude preselect to step down to the FAF altitude, arm GPSV, and let the EFIS capture and fly a coupled approach. At 6,140', you press MISSED. The EFIS de-couples, commands a 500 fpm climb, and switches lateral autopilot control back to the GPS (not HDG). GNS 430 sequencing resumes and the 430 waits until 6,400' before sequencing to the MAHWP. The EFIS commands a climb to and level off at the missed approach altitude while the 430 awaits the holding pattern. Slick.

Break, break. Re porpoising. The few EFIS-related pitch transients I've had have been smooth. If it's an out-of-trim problem, the transients will be jerky. You can get a feel for these by trimming at cruise speed, engaging the TT, and then slowing to approach speed. At some point, the stick forces will exceed the pitch servo's capability and its clutch will rapidly release, grab, release . . . even if autopilot vertical torque is set to 10 to 12.

John Nystrom
 
I am still not able to fly a LPV approach on GRT EFIS

I am now able to fly a coupled ILS and without porpoising thanks to the advice of John, Martin and other wonderful fellow RV'ers. I am still not able to fly a LPV approach all the time. I also can't always depend on the vertical guidance to be displayed (G/S) on the EFIS when I am trying to fly the LPV. This could be a real safety issue in the soup!!!!!

I heard from Mark from GRT and here is his reply about the issue of the 430W talking to the GRT EFIS re LPV approaches:

"We are testing updated software for the EFIS/430W commands. This should take care of the majority of your issues. When the software is released you will need to install two additional wires between the 430 and the ARINC module. As for the porpoise try to slightly adjust the GS gain. It should be default set to a value of 1.00. Try .9 first and see if it improves, if it does try .8. Use small steps to adhust the gain."
______________________________________________________________

I hope that it will not be too hard to connect these 2 wires. I can't imagine that it won't be a real mess. I have a hard time seeing the back of the 430W and I don't even know where the ARINC is. I was a wimp and had Aerotronics do my wiring.
 
More ^3

This is my third attempt to post this msg. I tried twice yesterday and after clicking "Submit Reply", was bounced to the log-on screen and the post never showed up. You can find me at [email protected]

Cleve,

Good to hear about the smooth ILS.

Re the GPS LPV, I flew an LNAV/VNAV today (yesterday now) and confirmed that the GPS GSI will not appear on the EFIS until the GSI unflags. I have a stand-alone CDI and as I approached the FAF, the GSI came off the top of case while the GSI was still flagged and before the EFIS GSI was visible. When the GSI had come down a bit, the GNS 480 switched from TERM to APPR* mode, the GSI flag disappeared, and the EFIS GSI appeared, all simultaneously. When the GSI was centered, the EFIS captured the GPS slide slope. I'm uncertain whether GSI validity info comes over the same 430-to-EFIS wire(s) as validity info for an ILS. If it doesn't, the software upgrade that Mark mentioned may be the solution. But, I don't think it's a software issue.

Re that upgrade, it will allow 430 lateral steering commands to pass through the EFSI. I mentioned this capability in my last post. The rewiring involves tapping into two wires that now carry the 430's ARINC output to your autopilot source switch and running the two new wires from the taps to one of the two 2-wire input ports on the EFIS ARINC module. That rewiring should be fairly easy because you can tap into the existing wires near the switch and the ARINC connector on the back of the MFDs should be accessible.

One of your EFIS ARINC ports now has 430 VOR-ILS input. The other may be free to use by the new autopilot wires from the 430. But, if you have a GTX 330 feeding traffic to the EFIS, it now comes via ARINC, and you must use that port for the autopilot input. You simply cut the 330 wires near the EFIS and splice in the autopilot wires. If you still want traffic on the EFIS, you must tap into a third wire, the one that carries RS-232 traffic from the 330 to the 430. The wire for that third tap will go to one of six RS-232 serial input ports on an MFD. The EFIS end is easy but finding the wire carrying the traffic from the 330 to the 430 may be more difficult because the wire is likely buried in the inter-stack spaghetti. The 232 traffic only need run to one MFD and interlink will distribute it to others. The upgrade will include code to support traffic via 232.

* The 430 doesn't annunciate TERM but uses more specific nomenclature that means the same thing.

John Nystrom
 
GRT has new software update

John, Martin, and others,

The weather here is lousy and I didn't get to try all the suggestions you have given me. I can't wait to get back in the air!

John, I will certainly use your instructions about wiring when the time comes. I am constantly amazed at the expertise of the members of this forum!!!

Today, I went to the GRT web site and found that they had a new update, "f". It did not mention having to do a hardware update for this latest update but the list of things that it corrects does not seem to include some of my issues. I guess that is coming later.

Wouldn't you know it, my memory stick is out at the hangar so I can't load this software right away.

I had a most welcome email from Jason at Aerotronics. He had seen our posts and he has grastiously offered to help me do the hardware update when the time comes. I have found they at Aerotronics do a fine job of wiring a panel and are great in the followup and support!!!!!
 
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